1. Field
Embodiments of the invention relate to cranes. More specifically, embodiments of the invention relate to luffing jibs for cranes.
2. Related Art
Cranes, digger derricks, and other heavy equipment utilize a boom assembly, a load line, and a winch to lift heavy loads. The winch is typically disposed on a base, and the load line runs from the winch along the boom assembly to an implement at the distal end of the boom. The implement then routes the load line downward so as to allow a load to be attached thereto. The winch may then be operated to reduce the available length of the load line and therefore lift the load.
Luffing cranes allow the crane to lift the load over a high or large obstacle. The luffing crane enables an operator to move the load laterally along the ground while elevated off the ground. The luffing crane keeps the load at a substantially static height above the ground while moving the load toward or away from the boom. The luffing crane accomplishes this by adjusting an angle of the luffing jib relative to the boom assembly while adjusting the boom angle.
The luffing jib of a luffing crane is typically very large and heavy. As such, it must be transported to a worksite separately from the crane. They also require an additional crane to assist in installation of the luffing jib. Further, luffing jibs also require the operator to run additional hydraulic lines to provide hydraulic power to the luffing jib. This procedure is very time- and labor-intensive. For example, the luffing crane requires three vehicles to be present (i.e., the luffing crane, an assisting crane, and a transportation vehicle). Because of the difficulty and time required to set up, luffing cranes are only used sparingly, such as when a specific need is present at a worksite. What is lacking in the prior art is a luffing crane that is easy and convenient to use.